More info @ MsExchangeTeam blog.

It is my distinct pleasure to announce today the global availability of Exchange Server 2010. This has been an amazing journey from conception to launch, and the team has delivered an unprecedented line up of innovations in this release. I am incredibly proud of the team and our product.

The dedication of the Exchange community working side by side with us to deliver Exchange 2010 has been inspiring for me. I want to thank you for your commitment over the past 3 years helping us develop new ideas, make product enhancements and test pre-release bits to ensure our final product is rock solid. I believe Exchange has the most impressive IT Pro and Developer community in the world today. We could not have shipped this product without you!

In return, I hope you realize the full value of everything Exchange 2010 offers. We are all working in a very challenging economic environment today. Being cost conscious has never been more important - but also helping your organizations differentiate themselves and compete effectively is just as critical.